Reagent feeder



L. D. MILLS REAGENT FEEDER Sept. 9, 1941.

Filed Feb. 6, 1939 s Sheets-Sheet 1 F'IE l INVENTOR. [00/5 9. M/'//5.Byw

A T TORNEY L. D.- M ILLS Sept. 9, 1941.

REAGENT FEEDER I Filed Feb. 6, 1939' s Sheets-Sheet 2 INVENTOR. IOU/'5/W/'//5 A TTORNEY Sept. 9, 1941.

L. D. MILLS REAGENT FEEDER Filed Feb. 6, 1959 3 Sheets-Sheet 5 FIE EINVEI'VTOR. [00/5 0. /W///5 (Ewe 4 .73%

ATTORNEY Patented Sept. 9, 1941 UNITED STATES REAGENT FEEDER Louis D.Mills, Palo Alto, cans, assignor to The Merrill Company, San Francisco,Calif, a corporation of California Application February 6, 1939, SerialNo. 254,865 7 Glairns. I (Cl. 221-425) This invention relates generallyto apparat is for feeding measured quantities of divided material. Moreparticularly the invention relates to apparatus useful in certainchemical processes, such as cyanide systems for the precipitation ofprecious metals from cyanide solution, where it is desired to feedmeasured quantities of a metallic precipitant like zinc dust at acontrolled rate.

It is an object of the invention to provide apparatus of the abovecharacter which will. be simple in mechanical design, and which willperate satisfactorily with metallic dust of ex tremely fine particlefineness.

Another object of the invention is to provide an apparatus of the abovecharacter which can be readily charged with a predetermined quantity ofmetallic dust, and which will discharge or feed the metallic dust with ahigh degree of accuracy and reliabiilty.

Further objects of the invention will appear from the followingdescription in which the preferred embodiment of the invention has beenset forth in detail in conjunction with the accompanying drawings.

Referring to the drawings:

Fig. 1 is a plan view taken along the line l--l of Fig. 2, and showingapparatus incorporating the present invention, in conjunction with theZinc emulsion cone of cyanidation equipment;

Fig. 2 is a cross-sectional view taken along the line 2-2 of Fig. 1.

Fig. 3 is a cross-sectional View taken along the line 3--3 of Fig. 2. p

The apparatus illustrated in the drawings makes use of a suitablesupporting framework if], which serves to carry the various workingparts. Suitable members of this frame carry journals H, for the verticalrotatable shaft l2. The circularly contoured disc i3 is mounted upon theupper end of shaft l2, and is formed of av suitable material such asstainless steel or a like non-corrodible metal. The annular peripheralportion 14 of the disc I3 is cupped upwardly as illustrated in Fig. 2,thus forming a shallow annular trough for receiving a charge of themetallic dust.

In order to drive shaft 12 and disc i3 at a constant rate, there is asuitable drive connection to an electric motor l5 or like source ofpower. In this instance motor it carries a gear reduction box i1, andthe drive pulley 88 from this gear box is connected to pulley l9 by belt2 I Pulley I9 is secured to the laterally extending shaft 22, which inturn carries a worm 23 for engaging the worm gear 24. Gear 24 is carriedby the additional shaft 26, which in turn carries a worm 21 forengagement with worm gear 28. Gear 28 is mounted upon the lower portionof the vertical shaft l2. With such an arrangelment shaft i2 is drivenat a relatively slow but constant rate, which may be varied inaccordance with requirements. In a typical instance where zinc dust isbeing fed into a zinc emulsion cone, for precipitating cyanide solution,the shaft l2 may make one revolution for one operating shaft of say 8hours.

In conjunction with the disc I3, means is employed for periodicallydisplacing portions of a charge of material placed upon the disc It. Inthis instance the displacing means is in the form of a wiper arm 3|,which is secured to the h0rizontal shaft 32. The free end of arm 3| isprovided with a projecting end portion 33 of flexible material, such asresilient rubber. As the arm 3i rotates its end portion 33 contacts andwipes across the upper surface of the curved disc portion it, wherebyany material in its path of movement is displaced over the outer lip ofthe disc. It will be noted from the cross-section illustrated in Fig. 2that the curvation of portion l4 corresponds to the segment of a circlehaving as its center, the axis of shaft 32. Also shaft 32 is disposed sothat the plane of rotation of arm 3! is generally vertical andcoincident with the axis of shaft l2.

The shaft 32 is also provided with a suitable drive connection to theelectric motor [6. Thus a pulley 34 is shown mounted upon one end ofshaft 32, and this pulley is connected by a belt 36 to a pulley 3'! onshaft 22. The speed of rotation of shaft 32 is made consistent with thespeed of rotation of disc [3. Thus where the disc I3 rotates onerevolution in 8 hours, the shaft 32 and wiper 3| may rotate at a speedof about 2 revolutions per minute.

It is desirable to provide a cover for disc I3 in order to protect thecharge of metallic dust from wind and moisture. The protecting cover 38in this instance is made of suitable sheet metal, and its side edges 4!are engaged in guide tracks 42. The forward portion of the cover isprovided with a slot 43, for accommodating the wiper arm 3|. When it isdesired to apply a charge of dust upon the disc I 3, this cover can beslid back to an out-of-the-way position, after which it isreturned toits normal position overlying the disc.

As previously mentioned the apparatus described above can be utilized toadvantage in connection with cyanidation equipment. Thus the drawingsillustrate a zinc emulsion cone 46, the lower end of which connects witha fiow pipe ill through which cyanide solution is conveyed. Extendingupwardly through the cone 46, there is a rod 48, the upper end of whichis loosely retained by the guide or journal 49. Rod 48 is periodicallyreciprocated by a rotating cam 5|, in conjunction with a tappet orcollar 52 mounted upon rod 48. Cam 5| can be driven from the same sourceof power as is used for the reagent feeder, namely the motor it. Thus itis shown mounted upon the horizontal shaft 53, one end of which carriesa pulley 54. Pulley 54 is connected by belt 56, to the pulley 51 onshaft 32.

The lower end of rod 48 carries a valve member 59, which cooperates withthe valve seat 6|. At periodic intervals cam elevates the tappet 52 androd 48, to permit a mixture of dust and solution to pass down tointermix with solution flowing through pipe 3?. In cyanidation systemsit is customary for barren cyanide solution to be supplied to the cone36, where it intermixes with the zinc dust.

In operating the apparatus described above a measured quantity of thedivided material is placed upon the disc 13, and is distributed by theoperator over the concave portion M. Fig. 2 illustrates such a charge ofmaterial after it is supplied to the disc. Where the apparatus is beingused with cyanidation equipment as pre-- viously described, sufficientfinely divided zinc dust is employed for a given shift, as for examplean 8 hour period. Upon starting the motor IS the disc I3 is slowlyrotated while the wiper arm 3| periodically moves across the upperconcave surface of the portion M. Each time the arm 31 wipes across thedisc, 2. portion of the charge is displaced over the outer lip of thedisc. Because of the arrangement of parts illustrated in the drawings,the discharged portion of the material drops into the zinc emulsion cone45, for mixture with the barren cyanide solution. The apparatuscontinues to function in the manner described until the disc it has madeone complete revolution, or has rotated sufiiciently far to causedisplacement of the entire charge of material. One now stops the motorl5, and after the protecting cover 38 has been moved to anout-of-the-way position, a new measured charge of material can beapplied to the disc.

One characteristic of the present apparatus is that it will giveaccurate results with metallic dust of extremely fine particle fineness.Such material is difficult to feed at a controlled rate, due to the factthat it does not tend to assume a distinct angle of repose. With thepresent apparatus finely divided zinc dust can be fed at a relativelyconstant rate, and without any spill or wastage of the material. It isalso characteristic of my apparatus that it can be readily charged by anoperator. It is a simple matter for the operator to apply a measuredcharge to the disc l3, because of the concave form of the peripheralportion [4.

I claim:

1. ma machine for feeding measured quantities of a divided material likemetallic dust, means forming a concave surface for supporting a measuredquantity of the material, a movable Wiper adapted to contact and wipeacross said concave surface, means for moving said surface at a constantrate relative to said wiper means, and drive means for said Wiperserving to cause said wiper to periodically wipe over said surface todisplace portions of the material from said surface.

2. In a machine for feeding measured quantities of a divided materiallike metallic dust, means forming an annular surface for supporting ameasured quantity of the material, said surface being mounted forrotation about a vertical axis, the surface being concavely curved toretain the charge of material, means for rotating said supportingsurface at a constant rate, a wiper arm mounted for rotation about ahorizontal axis located above said surface, the free end of said wiperarm being adapted to contact and wipe across said surface, and means forrotating said wiper arm at a constant rate.

3. In a machine for feeding measured quantities of a material likemetallic dust, means forming a surface for supporting a quantity of thematerial, a movable wiper adapted to con tact and wipe across saidsurface, means for moving said surface at a constant rate relative tosaid wiper, and drive means for said wiper serving to cause the wiper toperiodically wipe over said surface in a direction substantially normalto the direction of movement of the material into the region ofoperation of the Wiper.

4. In a machine for feeding measured quantities of a material likemetallic dust, means forming a surface for supporting a quantity of thematerial, means for moving said surface at a constant rate, a Wiper armmounted for rotation about a generally horizontal axis located abovesaid surface, the free end of said wiper arm being adapted to contactand Wipe across said surface, and means for rotating said wiper arm at aconstant rate, the surface being arranged to advance the material to theregion of operation of the wiper in a direction normal to the plane ofrotation of the wiper.

5. In a machine for feeding measured quantities of a material likemetallic dust, means forming an annular surface for supporting aquantity of the material, said surface being mounted for rotation abouta generally vertical axis, means for rotating said supporting surface ata constant rate, a wiper arm mounted for rotation about a generallyhorizontal axis located above said surface, the free end of said wiperarm being adapted to contact and wipe across said surface, and means forrotating said wiper arm at a constant rate.

6. In a machine for accurately feeding quantities of a finely dividedmaterial like metallic zinc dust, means forming a concave annularsurface for supporting a measured quantity of the material, a wiper arm,means serving to mount the wiper arm for rotation in a plane generallyperpendicular to the concave annular surface, the free end of the wiperdescribing a circle hav ing a radius corresponding generally to that ofthe concave surface, and means for continu ously advancing said surfacetoward the wiper to cause displacement of portions of the material fromthe same.

7. In a machine for accurately feeding quantities of a finely dividedmaterial like metallic zinc dust, means forming a concave annularsurface for supporting a measured quantity of the material, a flexiblewiper arm, means serving to mount the flexible wiper arm for rotation ina plane generally perpendicular to the concave annular surface, the freeend of the flexible wiper describing a circle having a radiuscorresponding generally to that of the concave surface, and means forcontinuously advancing said surface toward the flexible wiper to causedisplacement of portions of the material from the same.

LOUIS D. MILLS.

